The present disclosure relates to metal foams, more particularly, to methods to manufacture metal foams.
Reticulated metal foams are porous, low-density solid foams that include few, if any, intact bubbles or windows. Reticulated metal foams have a wide range of application and may be utilized in many aerospace applications.
Numerous existing manufacturing technologies for producing reticulated metal foams have been attempted. However, automated production of such reticulated structures may be rather difficult to implement as the ceramic investment often proves difficult to remove without damage to the resultant relatively delicate metallic foam structure. Further, the existing manufacturing technologies lack the capability to efficiently manufacturer relatively large sheets of metal foam as the weight of the ceramic investment is sufficient to crush and convolute the shape of the polyurethane foam precursors. This may result in castability complications, polymer burnout, and reduced dimensional tolerances.
Standard investment casting in a flask tends to insulate the cast metal evenly resulting in heat retention in the center of the mold. This may lead to porosity in the casting and much effort is expended in mold design to direct this internal hot zone to non-critical areas of the casting.